CHAPTER V 



FERNS; THEIR DISTRIBUTION AND ANTIQUITY 



' It has been shown that certain forms persist with very little 

 change, from the oldest to the newest fossiliferous formations ; and 

 thus show that progressive development is a contingent, and not 

 a necessary, result of the nature of living matter.' Huxley. 



The Ferns as a whole represent a section of the 

 vegetable kingdom which traces its ancestry as far 

 into the past as any group of plants. Impressions of 

 leaves on the shales of the Coal-measures and on 

 rocks of the earlier Devonian period are hardly 

 distinguishable in form and in the venation and 

 shape of the leaflets from the finely divided fronds 

 of modern ferns. Until a few years ago these 

 Palaeozoic fossils were generally regarded as true 

 ferns, and it was believed that ferns played a con- 

 spicuous part in the vegetation of the earliest periods, 

 of which we have any botanical knowledge. Con- 

 clusions based on external form must frequently be 



